Conventional implantable cardiac pacemakers typically include one or more medical electrical leads that deliver pacing pulses to cardiac tissue and sense the response thereto. Leads occasionally may have mechanical complications and/or MRI compatibility issues. Consequently, relatively compact implantable cardiac pacing devices have been developed that are able to deliver pacing pulses to cardiac tissues without leads. MICRA™, commercially available from Medtronic Inc., is one example of a compact implantable cardiac pacing device that is configured for implant in close proximity to a pacing site. Other microstimulators have been designed with short pacing leads referred to as leadlets. Exemplary microstimulators having leadlets or features thereof are shown in U.S. Pat. No. 7,949,395 B2 to Kuzma, US Patent Pregrant Publication No. 20040147973 A1 to Hauser, U.S. Pat. No. 7,082,336 B2 to Ransbury et al., U.S. Pat. No. 6,738,672 B2 to Schulman et al., U.S. Pat. No. 9,446,248 B2 to Sheldon et al., US Pregrant Publication No. 20110270340 A1 to Pellegrini et al., US Pregrant Publication No. 20090082828 A1 to Ostroff, U.S. Pat. No. 8,634,912 B2 to Bornzin, et al., U.S. Pat. No. 9,539,423, and U.S. Pat. No. 9,446,248 B2 to Sheldon et al. A need exists for improved delivery and fixation means for compact implantable cardiac pacing devices.